Thomas Staggs,
who has run the company’s parks and resorts unit since 2010 following a 12-year run as Disney’s chief financial officer, was named chief operating officer on Thursday, making him Mr. Iger’s second-in-command. All of the company’s operating divisions, including movies, television, consumer products and parks, now will report to him as well as to Mr. Iger.

Mr. Iger has said he will step down at the end of his current contract in June 2018. That means Mr. Staggs essentially has three years to prove to Disney’s board of directors that he is the best successor.

Since becoming CEO in 2005, Mr. Iger has run the company without a president or operating chief, and thus without an heir apparent for the top job. Before Thursday, no Disney executive besides Mr. Iger had oversight of multiple businesses.

Mr. Iger’s decision to elevate Mr. Staggs appears to have knocked out the latter’s main rival for the top job: CFO
Jay Rasulo,
who ran the parks unit prior to Mr. Staggs. Mr. Rasulo’s contract as CFO expired on Jan. 31, and he has not renewed it or indicated publicly whether he will stay on.

Messrs. Rasulo, Iger and Staggs weren’t available for comment, a Disney spokeswoman said Thursday.

People close to Disney have long considered Mr. Staggs—more outgoing and charismatic than Mr. Rasulo and more in the mold of Mr. Iger in his public appearances—the most likely internal candidate to become the next CEO.

As head of the parks unit, his primary focuses for the past five years have been developing and launching My Magic Plus, a wristband that acts as a high-tech ticket, planning device and wallet for visitors to Walt Disney World, and overseeing construction of Shanghai Disneyland, which was originally set to open later this year but was pushed back to 2016.

Mr. Iger has said that new technology and international expansion, particularly in China, are key to the company’s future growth.

Still, Messrs. Staggs and Rasulo had similar backgrounds, and some within Disney viewed the latter, with his aggressive focus on the bottom line, as a better choice.

Mr. Staggs, 54 years old, joined the company in 1990 in the strategic planning group after starting his career in investment banking and earning an M.B.A. at Stanford University.

Unlike Mr. Iger, who began his career in the television business, and his predecessor,
Michael Eisner,
whose background was in film, Mr. Staggs doesn’t have experience in the media-production parts of Disney’s businesses, where its most valuable intellectual property is created and—in the case of TV—where its biggest profits are generated.

However, as Mr. Iger has transformed Disney from a single creative entity into a collection of lucrative brands, including Pixar, Marvel, Star Wars and ESPN, an executive with Mr. Staggs’ financial acumen has become a more natural choice for the top job. When Mr. Iger, 63, named Mr. Staggs head of the parks and resorts business, it was widely regarded as a move to help groom him for a higher position by giving him operational experience.

The unit oversees five world-wide theme-park resorts—Shanghai will be the sixth—and employs 130,000 people. Mr. Staggs will continue to run the parks and resorts business until a successor is named.

In his new role, Mr. Staggs will be paid a base salary of $2 million annually with a target bonus of $5 million and target equity award each year of $8 million, according to a regulatory filing. Mr. Iger’s total compensation for the company’s last fiscal year was valued at $46.5 million.

Mr. Staggs’ new contract ends in June of 2018, the same time as Mr. Iger’s.